Sublimation
by Sabathiel
Summary: In which Izaya experiments with abstinence for a week. Shizaya. Raijin Days.
1. Chapter 1

**Disclaimer: I don't own Durarara!**

**A/N:** For the DRRR Kink meme~  
Dedicated to the OP

**Prompt:**  
"High school era. Shizuo/Izaya.  
Shizuo and Izaya decide to try abstinence for a week for some reason or another. Bottled up sexual frustration, skin brushing against each other in completely innocent situations, i.e. class, and lots and lots of kissing and groping while trying to get through the week."

* * *

It's the psychology teacher's fault that this happened.

He, the teacher that is, just _had_ to start a discussion on Sigmund Freud (actually, it could be Freud's fault that this happened…). Izaya, who liked psychology class, decided to do some extra reading about this Austrian neurologist and discovered his classic theory of sublimation which required being abstinent or some sort. Shizuo had no idea what the theory is about since he didn't even _like_ psychology (something about it being much too confusing) but he does understand the notion of abstinence. So when Izaya casually suggested it to him one day during their lunch period, he protested quite strongly.

"Of course you'd say 'no,' you brute," Izaya answered with a slight pout as he picked at his lunch (it was some sort of lumpy, fried crap that didn't seem the least bit appetizing). "You just don't understand Freud's works!"

"It's about psycho… psycho…" Shizuo muttered, trying to recall the word that sensei mentioned in order to prove Izaya wrong.

"Psychoanalysis!" Izaya snapped. "How do you not pay attention in class?" Of course Psychology would be his favorite class. He claimed to love humans so it was only natural for him to find the psychological aspects of it appealing. "Besides, Shizu-chan, it's only for a week. Consider it an experiment."

"I don't like being Shinra's lab rat. Why would I want to be yours?" Shizuo reiterated, close to squeezing his milk carton until it burst.

"Because," Izaya answered smugly, "Shinra doesn't give you head."

His comment made the flustered blond blush, but the brute was still stubborn to give up sex. "Why are we doing this again…?"

The brunet let out a frustrated groan and glared at the blond. "Why don't you ever listen to me? After this we're going to have work on your lousy communication skills. Freud's classical theory of sublimation reflects libido as the spirit and our sex drive is allowed a limited amount of expression due to the constraints of society, therefore, we need to turn our sexual urges into something productive."

"Like actual sex," Shizuo pointed out as a matter-of-factly.

"No, Shizu-chan, like art. Like socially acceptable things," he corrected. When Shizuo gave him a blank look, the future-informant rolled his eyes and muttered something like, "Uncultured brute!"

"So what's the experiment?" the 'uncultured brute' asked.

"I just want to see if you can actually convert your sexual frustration into something productive," Izaya answered. "I was going to take up cooking with the girls in their home ec classes. It's _only _a week, Shizu-chan. It'll be fun. Please?"

Oh, God. Izaya was giving him his pleading puppy eyes, the same puppy eyes that Shizuo can never resist. "Okay, one week," he said, holding up one finger to emphasize the point.

"Excellent!" Izaya answered much too cheerfully and the puppy eyes fall away with ease. "First, some ground rules. Obviously, rule one is no sex. Rule two, absolutely no removal of clothing! Three, I'll allow kissing, after all, I'm not that cruel."

"I hate Freud," Shizuo told him flatly. "I hate psychology."

"You hate everything," Izaya answered. "You hate me even though we fuck like bunnies." His vulgar words made Shizuo both blush and inwardly cringe. Izaya noticed this and grinned, slyly commenting, "Don't be a prude, Shizu-chan."

"I'm not!" Shizuo snapped, but Izaya only laughed in response.

When lunch is almost over, the brunet made a motion to get up, not even noticing the way his arm brushed against Shizuo's, and stretched. "Ah, see you later, Shizu-chan," he told him and headed off, carrying that stupid psychology book beneath his arm.

"Wait," Shizuo called out, getting up to follow the smaller man. Izaya looks over his shoulder at him with an amused look. "Um, that experiment you want… Let's start it tomorrow," he proffered, hoping that Izaya would be able to pick up on the suggestive overtone he was practically throwing at him.

Izaya grinned widely, and pulled Shizuo close by his tie. "Sounds like a plan," he murmured and kissed Shizuo deeply.


	2. Chapter 2

**Disclaimer: I don't own Durarara!**

_[Day 1 of the Development of Psychosexuality]_

The stupid flea decided to keep a daily log of his 'brilliant' experiment. Izaya kept all his writings in a fancy portfolio, the expensive kind with the faux leather and string to bind it shut. It was large and bursting with papers. Shizuo eyed the portfolio skeptically. "All that's just for this experiment?"

"Of course not, Shizu-chan!" Izaya replied cheerfully. "I'd just rather keep all my papers together. Makes it easier for future prospects, yeah?"

"What prospects?" Shizuo snarled.

Izaya shrugged, answering only with an elusive smile, choosing to keep secret of his future plans as an information broker. It was sort of cute actually, the smile that is, and Shizuo found himself attempting to kiss the brunet before class. Izaya backed away with a snort. "It hasn't been a day yet, and Shizu-chan already can't even keep his hands off me? My, I thought you'd at least be able to hold out longer than that." He smirked, dug through his bag for a pen, and quickly scrawled a note in his fancy, expensive portfolio. "See you," he then said nonchalantly as he headed off to class, not even bothering to show the blond what he wrote.

Shizuo let out a low growl and knew that by the end of the week, he'd probably lose his temper and wrestle Izaya for the papers. It was only natural and he was sure that Izaya knew it as well. Why else would the brunet be so protective over it? He trudged to his desk, and decided that he would prove Izaya wrong. He'd be the one to last longer than the stupid flea and by the end of the week, it would be Izaya, and not him, that would be the one sexually frustrated and begging for sex. And to do that, he'd ignore him and find another hobby. Shizuo vaguely recalled that the brunet decided to take up cooking. Perhaps, he could join the afterschool art club and learn to paint? Or check out the broadcasters? Or even join the alleged origami club? Shizuo made a point to keep away from contact sports and anything that was physical due to his strength.

Unfortunately, Shizuo made the mistake of mentioning it to Shinra that he was looking for something to do after school (in which Shinra cleverly commented, _"Aren't you already doing Izaya?" _and nearly had his arm broken for it) and the scientist decided that he would like to help in this psychology experiment just to see the results. He was a doctor after all, and who knows? This information could possibly be handy in the future (which only meant he'd probably try this with Celty, not that she'd care). Shinra spread the news that Shizuo was looking for an extracurricular hobby and before lunch, a shy girl approached the brute, suggesting that he'd check out the origami club after school.

"So there really is an origami club?" Izaya said incredulously at lunch. "And you're really going to join it?"

Shizuo shrugged. "You shouldn't be talking. You're learning cooking."

"Cooking is more important than paper folding. If there's no woman to make a sandwich for me, I'll have to do it myself," the brunet told him as a matter-of-factly. "Ah well, at least you're doing something other than me. Though, please do tell me what room this will be in. I'd love to see you fold a paper crane. Perhaps that is too elaborate. A fortune teller would do just fine."

The blond glared at him, definitely disliking the playful teasing. Oh, he'd show Izaya that he could fold a fortune teller _and_ a crane. "Room 1-7!" he snapped and pulled himself off the ground, brushing against Izaya as he did so. Izaya flinched at the contact, but it seemed that Shizuo didn't seem to notice, the flinching and the contact, that is. That was just so typical of Shizu-chan.

And after school, in class 1-7, the origami club met. The shy girl who invited him, (Misaki? Mitsuki? Natsuki? Shizuo really was terrible with names) greeted him cheerfully and proffered him a colorful sheet of square paper with a geometric pattern. "I guess just fold to your heart's delight!" she told him and led him to a seat next to her.

"Could you teach me how to make a crane?" Shizuo asked abruptly, surprising her and the other club members.

She blushed, but nodded, showing him the steps carefully. The result of Shizuo's origami came nothing close to resembling a crane or any other bird-like figure. It was deflated, crushed, and inside-out since Shizuo folded the wrong side of the paper. Misaki/Mitsuki/Natsuki laughed weakly, fetching him another sheet of paper to give him a second chance. The result was the same, deflated and crushed. Shizuo tore it in half when his annoyance settled in.

The girl then nervously suggested that he try to make paper stars, and returned shortly after with narrow strips of shiny paper. She patiently taught him how to fold the paper and how to 'puff' it up to give it its star shape. She and the other club members watched in amusement/horror as the brute fumbled with the strip of paper, ripping it as well as creasing it. The result was somewhat star-shaped, but not 'puffy' at all. Misaki/Mitsuki/Natsuki offered him words of encouragement and suggested that he not crease it so hard. His second attempt at making the star resulted in the paper unraveling when he attempted to fold the corners and 'puff' it up.

Izaya walked into class 1-7 with a container tucked beneath his arm just in time to hear the president of the origami club suggest to Shizuo that he stick to making fortune tellers. Shizuo lost his temper after, picked up the desk he was sitting at, and threw it into the president's face. "I QUIT!" he said loudly and stormed out of the class room.

Izaya laughed, teasing him on the walk home about it. "Well, Shizu-chan, there are other clubs you could try," he said, offering positive words. It was the least he could do, considering he was withholding sex from him. He paused and offered the container he was carrying beneath his arm to the brute. "I learned to make cookies in cooking club," he said, somewhat proud of this accomplishment. Shizuo smiled and dug into his pocket for a deflated crane, and two crooked stars, sheepishly giving them to Izaya.

_[Final Notes]_  
_Shizu-chan has bad hand-eye coordination..._


	3. Chapter 3

**Disclaimer: I don't own Durarara!**

_[Day 2 of the Development of Psychosexuality]_

At first, Shizuo considered that Izaya could have poisoned the cookies or filled them with elephant tranquilizers. He left the container of cookies on the counter with a note to Kasuka telling him that he'd better not eat one since Izaya made them. The next morning, he popped the lid off the container and skeptically examined the layers of cookies separated by wax paper and made a rough estimation of two dozen. Hesitantly, Shizuo picked one up and examined it. It was a buttery shortbread cookie with almonds and what appeared to be a generous dollop of chocolate on top. It looked quite appetizing and he popped it into his mouth, chewing slowly, and then he swore.

They were good. Like culinary _orgasm_ good.

Shizuo proceeded to scarf down two more cookies, cursing Izaya and his marvelous baking skills. He downed a bottle of milk and then went to head out the door, pausing for a second, only to return for one more cookie. Really.

"Did you like the cookies?" Izaya asked curiously when he met him at school.

"They were okay," Shizuo lied, not wanting to give Izaya the satisfaction of knowing that he needed said cookies to live.

"Oya? Well that's to be expected. There's always room for improvement," the brunet said cheerfully and Shizuo could only wonder how those immaculate cookies could have been improved. "What are you doing after school today?"

"Shinra said he'd take me to science club," the blond answered.

"You're not going to have fun at science club," Izaya said flatly. "Especially if you're going with Shinra-kaichou! They'll use big words that Shizu-chan's never heard of! Ah, but I'm sure it will be better than origami club," he said smugly. He laughed at Shizuo's scowl and pulled him close by the front of his shirt to give him an encouraging deep kiss. Izaya broke the kiss, leaving Shizuo dazed and wanting more. "You taste like chocolate," he told him thoughtfully and then smirked. "I'm glad you like my cookies."

"Tch! They could have been sweeter," he snapped and Izaya winced as his words packed an unnecessary punch. Izaya glared at him and stomped off to class without another word. Oh, he'd get him back eventually.

In class, Izaya made it a point to keep asking Shizuo for supplies, claiming that he'd forgotten his pencil bag at home. Each time Shizuo nonchalantly handed him whatever it was he needed, Izaya intentionally brushed his hand against Shizuo's fingers, wavering for a moment too long before pulling back. The blond was completely oblivious at first, but when he was handing Izaya a textbook, Izaya pressed his hand against his own and held it there for long seconds. Perplexed, Shizuo uncomfortably withdrew his hand away and shot Izaya a flustered (but adorable) look. Izaya smirked in response and then got up from his seat to head off into the bathroom. A few minutes later (by pure coincidence), the teacher sent Shizuo out of class to go retrieve something. Of course, he just had to bump into Izaya on his way.

"Oya? You're following me now?" he purred.

"You wish," the blond retorted, brushing past Izaya.

The brunet caught a hold of his sleeve and pulled him close by the belt loops of his pants. "Shizu-chan, how are you holding up?"

"What do you take me for? Some horny wreck that needs you?" Shizuo snarled, pulling back.

"I certainly hope so. I do like to be needed," Izaya answered smugly as he pressed his knee between Shizuo's legs.

The flustered blond pulled back and coolly commented, "You're going to ruin your experiment."

Izaya let out a bark of rich laugher. "And I thought you didn't even like this experiment," he remarked teasingly as he let Shizuo go. "But if you insist..." With that said, he gave Shizuo a small wave and then headed back to class, leaving him flustered, confused, and close to (if not) a horny wreck.

When he returned to class, Izaya actually had the nerve to ignore him. Midway, the brunet ended up pulling his own pencil bag (the one he claimed to have forgotten) out of his bag and unceremoniously dumped all of the supplies he had 'borrowed' back onto Shizuo's desk. Shizuo's mouth dropped open in shock as he realized the brunet was now attempting some sort of reverse psychology technique on him. Really, what did Izaya take him for? A brainless idiot? Oh, he'd show him.

"Heiwajima-san," an upperclassman called out, stopping him and Izaya in the hallway on their way to the rooftop for lunch. "Do you like baseball?"

Shizuo frowned. Izaya snorted. "Why?" the blond asked suspiciously.

"You'd be a good batter with that strength of yours," the student said with a grin. "How about you come by the pitching field after school today?"

"No thanks," Shizuo said flatly. "I'm going to science club with a friend." He didn't want to use his strength for sports. Not only did it give his team an unfair advantage, but there was always the chance that he could hurt seriously hurt somebody.

"I think it's a good idea," Izaya piped up suddenly, shoving his nose into Shizuo's business. "It'd be good for you to hang out with some jocky idiots."

Shizuo glared at him, but before he could decline, the student cheerily exclaimed, "Great! See you after school then!"

"You know how I feel about sports," the blond said accusingly to Izaya.

The brunet merely shrugged and gave him an innocent look. "I have no idea what you're talking about. But I will tell Shinra that you can't make it with him for you."

"Thanks," Shizuo muttered sarcastically.

After school, Shizuo unwillingly trudged to the pitching field where the team greeted him much more enthusiastically than the origami club. "You know how to play, don't you?" the upperclassman from before, Yamamoto, said cheerfully. He led Shizuo through a routine of stretches before offering the baseball to Shizuo, suggesting that he try pitching for starting. Shizuo sighed, heading to the center as Yamamoto went to bat. "Give me your best shot then!" he said with a wide grin and Shizuo suddenly had the urge to knock that smile off his face. Suppressing the violent urge, he winded back and threw the ball to the batter, watching his strength. Yamamoto didn't swing and then looked at him with a frown. "Heiwajima-san, I thought you were stronger than this. I'm sorry, but I'm a little disappointed."

"Give me the ball," Shizuo barked, ready to pitch again. He threw the ball harder this time, but once again, Yamamoto didn't swing.

Instead, he grinned stupidly and said, "You're holding out on me! Hewajima-san, it's nice that you're showing me mercy to that strength of yours, but our competition won't show us that kind mercy. Try again." It was the pitying look he got that did it. Shizuo let out a low growl and let loose. The moment the ball left his hand, he winced, praying that he didn't kill Yamamoto with a baseball. Much to his surprise as well as the other teammates, Yamamoto swung the bat and successfully hit the ball out the field, earning a home run. "That's more like it!" he exclaimed cheerfully, balancing the bat on his shoulder. "With that arm of yours, we can definitely win championships this year. Oi, Hewaijima-san, why don't you try batting?" he suggested, offering the bat to him.

Shizuo smiled, feeling somewhat accepted. Maybe baseball would be his new sport, but Yamamoto was starting to get on his nerves. He accepted the bat and took his place in front of the umpire. He nodded at Yamamoto's signal, blinked and the ball was already in the umpire's glove. He blinked again, surprised that he missed the ball.

"Yamamoto's the star player," the umpire told him as he tossed the ball back. "It's okay if you can't hit the ball."

"I'll hit it," the blond answered persistently, swinging at the flash of white that came in his direction. Once again he missed. Yamamoto laughed, asking if the blond needed to some of that kind mercy. "Just throw it!" he snapped.

Nearly breaking the bat from his tight grip, Shizuo swung the bat as hard as he could, ready to do anything but strike out on his first day. There was a loud pop as the ball connected with the bat and a whoosh as it went straight up into the air. The other team members' mouth dropped at the maximum height and speed the ball gained and Yamamoto grinned with the dreams of winning championships. Shizuo's triumphant grin morphed into one of horror when he saw Izaya casually walking to the field with a container beneath his arm.

"IZAYA!" Shizuo shouted as he went from cheerful to mortification in three seconds flat.

To his chagrin and the teammates' dismay, Izaya stopped dead in his tracks and looked at him confused. Shizuo almost swore that what happened next was in complete slow motion. The brunet looked up to the sky, shouted, "FU-!" and then the baseball collided with his head.

Shizuo was the first at his side, helping him up and making sure he didn't kill the smaller student. A large purple bruise was starting to blossom on the brunet's temple and he lay there limply, either unconscious or dead. The blond ordered the closest teammate to retrieve Shinra and Yamamoto quickly called for an ambulance. As he lifted Izaya up in his arms, he heard a small groan that sounded like, "you're quitting baseball."

At the hospital, the attending doctor and Shinra diagnosed Izaya with head trauma and a severe concussion. Izaya, completely conscious with half his face swollen up, glared at the both of them. "Really? I didn't realize it with this bloody lump on my head!" It was clear that he was upset. God forbid, if that stupid, inconceivable, uncultured monster decided to walk in right now. Which is exactly what Shizuo did. He came and hesitantly offered Izaya a get well card and a balloon that he picked up at the hospital gift shop. Shinra and the attending doctor instantly cleared out of the room so not to get caught in the crossfire. "A balloon? Seriously? I hate you!" Izaya snapped.

Shizuo winced, but tied the balloon's string onto the metal bar of the hospital cot. "I really am sorry," he said sincerely. "But it's your fault too. You're the one who just stopped walking and stood there waiting to get hit..." He stopped when Izaya nearly launched himself at the blond out of sheer rage. And Shizuo was supposed to be the violent one.

After many more apologies and bribe of ootoro, Izaya finally calmed down and stopped trying to maim Shizuo in some way. It was then that Shizuo realized how vulnerable Izaya looked and he leaned in to kiss him. He gently brushed his lips over the dark bruise on Izaya's forehead, and hugged him tightly, whispering more apologies.

Izaya let out a frustrated sigh, knowing it was impossible to stay mad at Shizuo when he was like this, all sad, sincere and downright pathetic. "I will forever hold this over your head," he told him flatly as he reached for the container he had been carrying with him before he had been hit and shoved it into Shizuo's arms. "We made apple pie. It's probably been crushed beyond recognition, but you _will _eat it." True to Izaya's word, the once-perfect pie was crumbled and broken in. Shizuo ate it regardless.

_[Final Notes]_  
_Keep Shizu-chan away from baseball and do NOT fall asleep when you're alone with him._


	4. Chapter 4

**Disclaimer: I don't own Durarara!**

_[Day 3 of the Development of Psychosexuality]_

Despite the attending doctor and Shinra's protests, Izaya just _insisted_ that he leave the hospital. As a result and out of guilt, Shizuo hovered over Izaya as a protective 'mother bear' figure and refused to allow him out of his sight. Usually, Izaya would find this endearing, but after getting his skull cracked by a baseball, he wanted to get as far away as possible from the blond.

"Don't take it personally, but just this one time, I'd rather my sisters play doctor and watch over me," he said frankly as they walked home. Seeing the guilty look in Shizuo's eyes, Izaya sighed warily and then added, "But you can stalk me all you want tomorrow at school."

"Eh? Shouldn't you be staying home?" Shizuo asked, concerned for the smaller student's wellbeing.

"And do what? I'll be bored," he whined. "And if something _does_ happen, won't you and Shinra be there for me?" He definitely had a point there. Shizuo still couldn't help but to dislike the idea of Izaya running around at school, but he relented after Izaya gave him those damn puppy eyes as well as a promise to wait for him to pick him up.

The next day at school, girls that Shizuo had never seen before went up to Izaya and fawned over him, cooing about the bruise on his face. After a few seconds, he realized that those were the girls from Izaya's cooking club. The brunet didn't seem to mind as he shamelessly basked in the attention.

"You're going to be okay, right, Orihara-sama?" one of the girls asked with wide eyes as she examined the bruise.

"Of course, of course. I'm not going down that easily," he said charmingly.

"Do you need somebody to ice it for you?" another girl asked.

"You know, that actually wouldn't be-"

Izaya was suddenly cut off by Shizuo forcefully dragging him by the arm away from the girls growling, "If anybody's icing it, it's me!"

"Oya? Is Shizu-chan starting to get possessive?" Izaya asked with a wink. "Oi, where are you going after school today so I know to avoid it?"

Shizuo looked at him guiltily and admitted, "I'm not."

"No? But we were making such _good_ process," the brunet said slyly. The blond looked at him like he was crazy. Maybe Izaya was making good process, but Shizuo was most certainly _not_. If anything, his failures in both clubs left him even more sexually frustrated. The brunet let out a loud, dramatic sigh and then said, "Ah, Shizu-chan, would you like to come to cooking club with me then?"

Shizuo stared at him, surprised that he was willing to share cooking club. "Those girls...?"

"Hm? They wouldn't care. They find a domestic man sexy and charming," he replied nonchalantly.

"I don't think baking really counts as cooking..." Shizuo commented quietly.

"Oh? I don't think you were complaining when you completely devoured the cookies and the apple pie!" Izaya reiterated. "After school, room 2-3!" he reminded and then headed off to class.

During this time, Shizuo went to apologize to Yamamoto for quitting the baseball team, thus crushing his dreams of winning championships. The upperclassmen laughed and cheerily wished him luck in finding the right club and he would always be welcomed back into baseball. Maybe Yamamoto really wasn't _that_ bad after all.

After school, Shizuo headed to the cooking club's room where he found that Izaya was the only guy there amidst several girls. The brunet was idly flipping through a recipe book at one of the counters and actually lit up when he saw Shizuo enter. "You actually came," he said, sounding impressed. "Does Shizu-chan already know how to cook?"

"Nope," he answered frankly, looking at all the utensils laid out and a bag of white powder which was probably flour.

Izaya snorted, muttering something about uncultured monsters in society before stepping in front of the counter where Shizuo realized he was wearing a frilly pink _Hello Kitty_ apron. Shizuo's mouth literally dropped. Izaya followed his gaze with a frown to the apron and shrugged. "Cute, neh?" he asked teasingly, turning away to retrieve measuring spoons and cups.

Shizuo certainly did not remove his eyes from the apron, admiring the way the frilly bow was tied so perfectly that the ends framed Izaya's ass rather nicely. The blond suddenly tore his gaze away from Izaya, realizing what a pervert he was being. He really was sex-deprived...

"This is the cake recipe. Just measure out what I need. I can cook the rest," Izaya said, pushing cups and spoons towards the confused blond as well as ingredients. Shizuo picked up the closest cup, studying the 'one cup' measurement on it when suddenly a wad of black fabric was tossed his way. He clumsily fumbled with it, before unraveling it and realizing it was an apron. A rather girly apron. "_Monokuro Boo!_ Cute, huh?" Izaya said waving at him to put it on.

Sighing in defeat, Shizuo obeyed, struggling to tie it correctly before one of the girls came to assist him. He watched as everybody in the club fell into a rhythm of mixing, stirring and measuring. Shizuo awkwardly did as he was told, watching Izaya out from the corner of his eye. The brunet was enthusiastically chatting with one of the girls while attempting to crack an egg one-handed without getting the creamy white shells into the mixture.

Izaya would return to the blond's side, every now and then just to make sure he was getting the recipe right. As he did so, he would brush his fingers against Shizuo's discreetly as he read the recipe, or maybe even reach out wipe flour from his smudged cheek. The third time he returned, he frowned, realizing he was missing a few ingredients. Putting the book down, he declared that he had to go to the store. "Eh? Orihara-sama, should be going to the store with that bruise? Why don't I just go get it for you?" one of the girls exclaimed, worried. The other girls in the club nodded their heads in frantic agreement. Now Shizuo understood why Izaya really liked cooking club; all those girls were at his beck and call.

"I'm fine. Shizu-chan will make sure I don't die on the way," he said with a shrug, greatly disliking how everybody assumed he was no longer independent just because of a silly baseball to the head. "It's just down the street!" The girls looked at him skeptically, but relented nonetheless. Izaya put his cake batter into the oven before leaving.

He left the classroom still in his apron with Shizuo following close by. The walk to the store was full of chatter, mainly on Izaya's part. He seemed really happy that Shizuo was now in cooking club, and nothing was really going wrong except for a baking powder/baking soda fiasco but that was a mistake any newbie would have made. He made quick work of his errands, buying what he needed and then he was out, cheerfully heading back. Shizuo, grateful that Izaya was being nice to him despite nearly almost killing him, shyly searched out the brunet's hand, entwining their fingers together.

Hand in hand, they returned to the school, silently heading up the stairs when Shizuo stopped at the stairwell abruptly. Izaya hadn't noticed and continued a few steps up until he realized he was pulling dead weight. A confused look spread on his handsome features and before he could question it, Shizuo pulled sharply on the brunet's arm, causing him to tumble down the stairs into the blond's arms where they met in a kiss.

"Mmm," Izaya moaned against his lips as the grocery bag slipped from his fingers. Breaking away, he gasped, "It's the apron, isn't it? I guess it makes up for this unattractive bruise."

"Maybe," Shizuo answered in a deep, sultry voice. He kissed him again, wrapping his arms protectively around the smaller student. They kissed, alone in the stairwell. Izaya slid his fingers beneath Shizuo's shirt, tracing hard muscles and reveling the way they rippled beneath his fingertips. Shizuo pressed his knee between Izaya's legs, grinding against his tight pants as well as forcing the brunet to spread his legs.

Shizuo fumbled with Izaya's belt, wondering if they both were going to give in and screw (for lack of a better word) the experiment, when a timer went off from the cooking classroom and Izaya, without a second thought, pulled away, grabbed the grocery bag off the floor and dashed off, exclaiming something about how his cake was going to burn.

Shizuo growled, extremely frustrated now as he trudged after the smaller student. Izaya really was a tease sometimes. He watched as Izaya slipped on oven mitts and pulled his cake pan from the oven. After inspecting it carefully, he removed it from the pan onto a cooling tray and then began to mix up some icing, completely disregarding Shizuo. The girls put their cakes in the oven and then told Izaya they were going to the library and catch up on some homework really quick, leaving them alone in the classroom. Boldly, Shizuo hugged Izaya from behind, pressing his chest to his back.

Izaya didn't seem to mind and wordlessly continued to make his icing and cake filling. After a while, he pulled away from Shizuo's warm embrace to ice his cake. "How does it look?" Izaya asked, still wearing his apron with a smudge of chocolate on his cheek.

"Looks... good," Shizuo said firmly, not even looking at the cake.

"I'm talking about the cake," Izaya answered flatly.

"So am I," the blond replied unconvincingly.

"Perv," the smaller student snorted as he finished icing the cake. Finished, he placed his masterpiece into the fridge to cool. The girls' cakes were also done, and Izaya was kind enough to pull those out of the oven for them. He cleaned up a bit and then retrieved two spoons to finish off the leftovers of his chocolate icing. "Do you think it's too sweet?" Izaya asked, offering a spoonful of icing to the blond.

Shizuo tasted it, savoring the chocolatey heaven and then answered, "It's perfect." Right after, he leaned in and kissed Izaya on the cheek, getting rid of the chocolate smudge from earlier. "Even better."

Izaya snorted at the cheesiness of his words, but continued feeding him chocolate icing. Shizuo eventually decided to go back to kissing Izaya, still annoyed that Izaya had chose his cake over him. "Not here," Izaya murmured softly, weakly protesting. He tangled his fingers into Shizuo's blond hair regardless, enabling the kissing. "It really is the apron, isn't it?" he teased, catching himself on the counter.

Shizuo muttered a soft "shut up!" and continued kissing him deeply. Izaya groaned, tasting chocolate off his lips and leaned back, arm pressing against one of the still-hot cake pan that Izaya had taken out earlier.

"Ow! Ow! Ow! Shizu, let go!" Izaya hissed, jerking away from the hot cake pan. He scowled, looking at his marred skin that was now swelling into the shape of the cake pan's corner and then glared at the blond. "And this was going so well, too," he said in sarcastic defeat, heading to the fridge to get ice cubes (for his arm, and most likely, later for his head). Well, that certainly was a way to kill the mood. Izaya ordered Shizuo to grab the first-aid kit in the cupboard for bandages, while muttering how this experiment was probably a mistake on his part.

If anything, at least Shizuo didn't ruin the cake.

_[Final notes:]  
Apparently, Shizu-chan has an apron fetish. Who knew?_


	5. Chapter 5

**Disclaimer: I don't own Durarara!**

Also, I'm pretty sure Erika and Walker didn't go to Raijin, but I love them and I like the idea so bear with me, please. 

_[Day 4 of the Development of Psychosexuality]_

"Do you know why I like Fridays the best?" Izaya asked as a conversation starter.

Shizuo looked at him blankly and then answered, "I thought you liked Mondays..."

"I used to because Monday is the day that most humans hate! But I now I shall conform and start to like Fridays the best, do you know why?" he asked again.

"No, I don't know why. Enlighten me, please," Shizuo replied, wondering where this conversation was leading to. He also wondered why people liked some days the best. A day was just a day to him.

"I like Fridays best because of you. It means that this is the last day of the week and there's no other school clubs for you to go to and no possible way for me to get beaten up in some shape or form!" Izaya said, starting to become hostile. "Right, Shizu-chan? Because tomorrow I have cram school and I won't have to see you until later and you'll be playing video games in the arcade and whatnot. So let's try and get through today without putting me in harm, kay?"

Shizuo scowled, temper flaring. "Shut up, you ingrate. It's not like I hurt you on purpose! You _know_ I would never do that to you."

Izaya sighed, defeated and glanced at Shizuo uneasily. "Yes, I know. I'm sorry."

"It's okay. I'd be mad too if I was hit in the head with a baseball and then got burned... How's your arm?"

Izaya smiled wryly and rolled up his sleeve to inspect it. It was swollen and blistered and not a pretty sight. "I think it's getting better," he said insincerely. "What club is today because I am kicking you out of cooking club myself."

"No clubs, I'm on cleaning duty today with Kadota," Shizuo answered. "Lucky you," he added with venom.

"Dotachin?" Izaya repeated, dismissing that snarky comment. "If he has Erika-chan and Yumasaki-kun with him, then you're the lucky one," he said snidely, knowing something that Shizuo didn't. "Ah, well, have fun. The girls and I are making onigiri in cooking club. If you're nice, maybe you'll get one~!"

"Can it, flea," Shizuo growled.

Izaya pouted adorably and waved him off. "Ah, Shizu-chan, I've been meaning to ask, for experimenter's sake, how are you coping with Freud's theory?"

"I still think it's a bullshit theory and I still don't get it and I still hate it," Shizuo said flatly.

"Of course you'd say that," the brunet scoffed and made a mental note to work on the blond's communication and listening skills after the experiment. "But for the record, have you done anything productive?"

Shizuo didn't answer and Izaya rolled his eyes. "I've had more time to do homework," the blond said after a short period of silence.

"Doesn't count," the smaller student replied, shooting him down without a second thought. "It needs to be artistic so baseball wouldn't count either."

"How is cooking an art?" Shizuo asked skeptically.

"It's culinary art! It's artistic!" the brunet snapped. "It's a passion! The way the tastes meld together, your use of spices, the aromas. How is that _not_ an art?"

Shizuo deadpanned. Shaking his head at Izaya's sudden femininity, he stalked off to class without another word leaving the future-informant standing alone and aghast.

After school, Shizuo met up with Kadota in hopes to finish cleaning duty in record time. Then he'd be able to go home and play video games or whatnot. When he was in the middle of moving all the desks and chairs to one side of the room so Kadota could sweep up, two bouncy otakus suddenly burst in with every intention of distracting them.

"Ciaossu Dotachin! Ciaossu Shizu-chan!" Karisawa Erika said cheerfully as she came in with a bag bursting with manga.

"Hello Kadota-san, Shizuo-san," Yumasaki Walker added following Erika to the desks and chairs that Shizuo had moved.

"You're not even planning on helping are you?" Kadota asked, looking to Erika and Walker who were emptying their bags of their manga hoard as he began to sweep the floors.

"Of course not, Dotachin!" Erika replied sweetly as she sat on top of one of the desks, swinging her legs merrily as she began flipping through the latest _Ga Rei_ release.

"Our cleaning duty's not 'til next week, Kadota," Walker said apologetically as he sat next to Erika on the same desk, reading over her shoulder.

"Hey, Shizu-chan, you still going out with Izayan?" Erika asked, looking up from the manga. Shizuo blushed and Walker sighed wearily, already knowing where this conversation was heading. "Neh, Shizu-chan, tell meeeeee!"

"Don't!" Walker and Kadota said at the same time.

"Yes," Shizuo said in a clipped tone, giving Erika none of the delicious details she was craving. He quickly went over to the chalkboard and began to clean the board and then the erasers.

Erika pouted and went back to her manga once realizing that Shizuo had no intention of talking about Izaya or his horrid psychology experiment. "Yumacchi, when do you think Ken-chan will confess to Kagura...?"

"Well, Karisawa-san, I think..." Walker answered in hushed whispers.

The rest of their anime and manga talk fell into soft murmurs as Shizuo and Kadota quickly finished their cleaning duty.

"Shizu-Shizu, we're going to Sunshine 60 to meet Togusacchi. He's buying Ruri's new CD. Want to come with?" Erika offered. "We can buy more manga or play at the arcade. Izayan can come too."

Shizuo scratched the back of his head and looked to Kadota and Walker to make sure he wasn't intruding. "I'll let Izaya know. I think he's still here." Kadota and his gang nodded as Shizuo headed up towards the Home Ec classes where Izaya would be with his cooking club. He found the brunet casually lounged in a desk eating onigiri balls and reading a comic book. Shizuo relayed the invitation to him and he seemed quite happy to go along.

Stretching he said, "Let me just clean up here. Eat onigiri. We made too much. You might as well give some to Dotachin and the otakus."

At Sunshine 60, Kadota left the group to find Togusa, promising to meet them later at the bookstore. Erika and Walker led the way ecstatically, squealing about upcoming book signings and conventions. They settled themselves into the manga section, establishing a nest, and Izaya led Shizuo away to look at cookbooks, much to the blond's dismay.

"Don't lean against the book shelf; you'll knock it over," Izaya chided softly as he skimmed through a cookbook, leafing through the pages until he found something that looked appetizing. Shizuo let out a soft growl, eyes glued to the exit. He had come to the bookstore for comics, not cookbooks. "Keep up with that attitude, and I'll take my own sweet time," Izaya muttered, reading the hostility Shizuo was unconsciously giving off.

Shizuo paused, looking around for Kadota and the otakus. They were probably on the other side of the bookstore where all the decent books were. In fact, nobody else was really browsing cookbooks, causing Shizuo to realize that they were the only two in the section. Izaya was too engrossed in the recipes to even notice that the blond was plotting something and he jumped when warm arms abruptly wrapped around his waist, pressing his back against a warm chest. Izaya tried to ignore the needy blond and attempted to focus on reading but when he felt blond hair brush against his cheek and lips on his neck, he knew it was a lost cause.

"Shizu-chan, what are you doing?" Izaya murmured, leaning his head back against Shizuo's shoulder. "Not in public."

"That's never stopped you before," Shizuo murmured against his skin. "And we're the only ones here."

"Haha, so it would seem," the brunet chuckled, looking around quickly to make sure the coast was clear. He set the cookbook back onto the shelf, turned around and kissed Shizuo fully on the lips. Shizuo kissed him deeply, pressing the smaller man against the bookshelf as their tongues entwined in a hot kiss. It was heated, frantic and passionate, fueled by the thrill of possibly getting caught. Amused, Izaya wondered if Shizuo would really take him right here and now just because he was frustrated.

Ah, Shizuo really was unpredictable at times.

Izaya was so rudely pulled from his thoughts when the brute assaulted his neck with his lips and tongue, nudging his collar out of the way with his nose and finding Izaya's weak spot on his collar bone. The brunet held back a moan, reaching back to grip one of the shelves, displacing books as he did so. Shizuo lavished his neck with love bites, making sure to establish his claim on the future-informant. His fingers slid beneath Izaya's shirt, sliding up to tweak his nipple. The blond pinched it gently, stimulating the nerve endings and making Izaya see stars.

"Shizu... chan..." Izaya murmured as Shizuo pushed his shirt up and pressed his mouth against an erect nipple. His tongue flicked against it, circling the nub before biting down. Izaya let out a soft moan, panting as he threw his head back against the bookshelf. His knees felt weak, his weight now only supported by the blond ravishing his senses. Shizuo was grinding his hips provocatively against Izaya's and he attempted to slip his hand into Izaya's pants.

The bookshelf wobbled dangerously and before Izaya could stop Shizuo, his heart stopped as he heard Erika and Walker's voice from behind the bookshelf. Panicking, Shizuo, unable to control his strength, pushed Izaya away into the teetering bookshelf, causing it to topple over and nearly hit Erika and Walker. The two otakus jumped back in surprise as the bookshelf and an almost shirtless Izaya came crashing down. Walker, in his surprise, dropped the stack of papers he had been carrying and Izaya's papers spilled out from his portfolio.

Papers were everywhere. Izaya cussed and fell to the ground, quickly gathering up everything that was his. Erika and Walker bent down, trying to separate their papers from Izaya's. Walker panicked, quickly gathering up his precious fan art while Erika seemed to just grab everything in sight whether it was hers or not. The bookstore manager came and kicked the four of them out after forcing them to pick up the shelf and restack the books.

Guiltily, they had to explain to Kadota and Togusa why they got kicked out (though Izaya and Shizuo left out a considerable amount of details that Erika would have killed somebody for) and they decided it would be best to call it a day. Togusa drove off in his beloved van, taking Kadota with him while the four headed down to the train station. Izaya's train was the first to arrive and he was the first gone, bidding farewell to Shizuo with (much to Erika's delight) a quick goodbye kiss.

"Oh no!" Erika wailed suddenly after Izaya's train was long gone and the platform had cleared. Shizuo and Walker looked to Erika confused as she held up several sheets of paper in Izaya's handwriting. "It's not my fan art!" she exclaimed, so distraught that she hadn't realized she was carrying the motherload of information.

Shizuo's mouth dropped, instantly recognizing the papers. The kind of paper that came in with the stupid, expensive, faux-leather one. The one that held Izaya's life's work. The exact same one that held all of Izaya's documents of the sublimation experiment, including his notes on the blond. Shizuo reached to snatch it from Erika's grasp.

Unfortunately for him, she noticed that he seemed even more distressed than she did and she instantly knew something was up. Erika pulled the portfolio out of his reach and frowned, examining it carefully. "What's this, Shizu-Shizu?"

"It's Izaya's. I can give it back to him. He needs it for cram school tomorrow," he lied.

Erika raised an eyebrow and looked to Walker. "It seems important," she commented, undoing the string to peek inside. "Development of Psychosexuality? What's this, Shizuo?"

"It looks like Izaya-san is conducting a psychology experiment on Shizuo-san," Walker observed, reading it over Erika's shoulder.

"It's detailed. And it's all about you," Erika said with a smirk as she read up the juicy details she wanted. "Izayan's denying you sex!" she squealed. "That must be why you're so moody! You're sexually frustrated!" She let out a fangirl squee and ranted about a fanfiction idea.

Luckily for Shizuo, Walker pried the reports out of Erika's hands and offered it to Shizuo. "You'd better get it back to Izaya-san," he said with a nod. "It seems important."

Shizuo took the papers gratefully, safely storing it into his school bag as Erika begged for him to make copies before Walker dragged her onto their train home. When they were gone, Shizuo looked down at his school bag, thinking of the reports. Izaya claimed that he had documented _everything_ that he observed in the experiment. What he'd do with the information, Shizuo had no idea, but he was starting to get curious on the things Izaya noticed about him. It was starting to become Pandora's Box and he knew that he shouldn't be reading it but... the train ride home would be a long one...

_[Final Notes]  
The next day at cram school, Izaya frowned when he pulled his portfolio out of his bag, sensing that something was a bit off. Imagine his shock when instead of his cram homework or precious information, he pulls out a very graphic yaoi sketch Erika had drawn in her spare time. Let's just say he saw Ed and Mustang in a way he never ever EVER wanted/wants/or would ever want to see._


	6. Chapter 6

**Disclaimer: I don't own Durarara!**

**A/N: I got lazy with the review replies for last chapter OTL.**  
**Thank you to all who reviewed!**

_[Day 5 of the Development of Psychosexuality]_

When Izaya saw the graphic yaoi drawing, his first thought was, "Holy shit! How did this get in here...? Wait, I could actually try this position with Shizu-chan..." which was immediately followed by, "Oh, crap. Erika has my cram homework and my psychology experiment..."

A pause and then the realization hit him. Erika has his detailed observations of a sex-deprived Shizuo and only God know what she'd do with it. Just this once, Izaya skipped cram school to go set things right before Shizuo finds out and snaps his neck.

Izaya had taken the first train to Erika's apartment. She sleepily answered the door in her anime-themed pajamas and looked at the brunet with surprise. "Eh? Izayan? Why are you here so early? Shizu-Shizu said that you have cram school at this hour."

"I skipped it," Izaya replied hastily. "It seems that my papers have been mixed up with yours," he said, returning her graphic drawing. "Where are my papers?"

"Oh, Yumacchi gave them to Shizu-Shizu so that he could return it to you himself," she yawned, looking over the Mustang/Ed fan art before setting it down somewhere behind her.

"You did what?" Izaya gaped, paling at the thought of Shizuo reading the notes.

"Sorry," she answered with a shrug, closing the door and returning to sleep. "By the way, you totally made my life with that report," she murmured through the closed door.

Izaya froze, horrified, and wondering what Shizuo was going to do to him now. If Erika had read it, then Walker read for sure. And if the two otakus had read it, Shizuo must have read it. Then why Shizuo didn't call him up to shout at him the night before? It made no sense. The angered blond would have called him up or at least storm all the way to his apartment and break down the door. Could it be that he hadn't read it yet?

Yes, Shizuo hadn't read the report yet. He had left it on his desk, unread, and deprived himself of sleep that night wondering if he had a right to read something about him. Pulling himself from his bed, he sat at his desk and studied the report's cover carefully. It was completely blank save for the small handwritten 'Heiwajima Shizuo' in the dead center. He gritted his teeth and clenched his fist, still trying to choose between betraying Izaya's trust or not...

Well, since he worded the situation like that, _clearly_ he should not betray Izaya's trust. But what if something unfortunate happened, and he lost the cover page and he ended catching a few choice words on the first page of the report? Then he wouldn't _really_ be betraying Izaya...

Shizuo looked behind him cautiously as if somebody were watching him, took a deep breath, and then flipped to the first page of the report. His school picture was paperclipped to the sheet and beneath it was just basic information: name, birthday, blood type, height, weight etc. There was nothing incriminating yet.

The curious blond flipped to the next page and frowned seeing his high school transcript and several middle school report cards. There were also hospital records from each time he had been admitted after breaking a bone (which was a lot of times) and Shizuo had to wonder just how on earth did Izaya get his hands on these supposed-to-be confidential documents.

Past the documents were silly things reminiscent of graduation slambooks like favorite quotes, food, actor/actress, movies... Some of the questions were blank, like the animal one and the actor/actress one and some of the other answers looked really familiar. He stared at them, puzzled, and then realized that these were the same answers he had written in Shinra's slambook from middle school.

After the questionnaire was an essay of Izaya's theory of Shizuo's strength. He merely skimmed over it, seeing too many big words and wondered if Izaya had written it with Shinra's help. There were minor notes about Kasuka and Shizuo had to wonder if the brunet had a separate file for his little brother. Fed up with all the fluff and not actually finding anything helpful, Shizuo decide to cheat and flip all the way to the end and then he hit jackpot.

Half an hour later, Izaya arrived at his door, knocking frantically. Kasuka went to answer the door, but stopped when a seething Shizuo stormed down from his room. The blond snatched the cold bowl of cereal from his brother's hands, opened the door and blindly threw it. It was only thanks to his quick reflexes that Izaya managed to dodge it and he cringed when the porcelain bowl shattered behind him.

"You read it," he said sheepishly. Shizuo's response is to growl and lunge at him. Kasuka sighed, closed the door behind the two and went to get another bowl of cereal. Izaya stepped back, minding the cereal slosh on the pavement and ducked a punch from Shizuo.

"Stay still, fucking flea!" Shizuo growled, trying to hit him again.

"No thanks," the brunet said, keeping his distance from the seething mass of destruction. "I have to ask though, which part was it that you found offensive?"

"The fucking hypothesis! _Heiwajima Shizuo is nothing but an uncultured brute who thinks with his well-endowed cock and is unable to do anything right besides sex!_" he roars.

"Shizu-chan, let's keep it down a little. You have neighbors, remember?" Izaya said uneasily, still backing away. "Frankly, I don't find anything offensive with that statement! 'Well-endowed' is a compliment!"

"_Heiwajima Shizuo might be at risk for a brother complex. I wonder if he's going to dump me?_" the blond growled.

Izaya laughed uneasily. "Alright, that one might be a little overboard. What else you got?"

"How about the whole section dedicated to my flaws in bed?" Shizuo snarled. "Why would you even document these things? When you write these things, I have to wonder, are you using me for sex?"

"Shizu-chan, how could you say such a thing?" Izaya asked, looking appalled, but then again, it could just be good acting. "There wasn't anything in the report that suggested that!"

"_Heiwajima Shizuo's well-endowed cock certainly makes it worth it to keep dating such an uncultured brute._" he said flatly. Izaya instantly paled with a look of pure horror in his eyes. "Fifth page from the end. Middle paragraph. First sentence," Shizuo added, proving that he was not making this up.

"Shizuo, you did read what followed, didn't you?" Izaya answered. "You can't just pull words out of context."

"_He certainly lives up to my expectations of being a monster, and oddly, he seems more prone to destruction when he's sexually-deprived. A bit of a turn-off_. Trust me, Izaya, I read the report," the blond hissed, cornering the smaller student.

"But you are destructive," Izaya said calmly, trying to devise an escape plan. "I've got the wounds to prove it."

"Enough with the guilt trip!" Shizuo snapped suddenly, swinging his fist.

Izaya stopped mid-rambling, ducked, and looked at him with wide eyes. "I beg your pardon?" he gaped, eyeing the crater in the wall left from Shizuo's fist.

"I've apologized for giving you a concussion and for burning you and for knocking a bookshelf on you," Shizuo stated. "I've apologized for it all and you keep bringing it up."

"Shizu-chan, I told you I would this over your head forever," Izaya answered as a matter-of-factly, glad that he got the blond's mind off the report. Unfortunately, from the looks of it, it seemed that it wasn't going to help Izaya escape unharmed.

"That's doesn't mean you need to be a whiny bitch about it!" he hissed.

"Whiny bitch?" Izaya echoed, appalled by the blond's choice of words. "What do you take me for, a nympho?"

"From the way you've been acting lately, sure," Shizuo reiterated.

"Ha! That's a good one, Shizuo. You've been _nothing_ but a horny mess since day one of this experiment!" Izaya countered. "You can't even keep that sex drive under control and as a result, I get caught in the crossfire!"

"There you go again," the blond growled. "Let's just call it collateral damage from _your_ stupid experiment."

"It's not stupid! Freud was a fucking genius! It's you! You're the one with the screwed up sex drive, you nympho!" Izaya shouted, raising his voice to be louder than Shizuo. It was instinct, really, as in 'the louder person in the argument wins' kind of instinct.

"You just came up with this experiment to manipulate me!" Shizuo answered, raising his voice as well. "That's all you ever do. You manipulate people and you throw a whiny, bitchy temper tantrum if you don't get your way. You're nothing but a manipulating bastard. Did you manipulate me into this screwed up thing we call a _'relationship'_? Probably because you only use me for the sex!"

Izaya's eyes went soft at the last accusation. It was only for a split-second and then his defensive mask was up. Izaya could tolerate anything from Shizuo, all the insults and the abuse, but the one thing he couldn't stand was Shizuo doubting his sincerity in their 'relationship'. But now, according to Shizuo, they didn't even have one. "Go fuck yourself because you're definitely not getting any from me," the brunet spat vehemently. "We're done, Shizuo."

Shizuo was too angry to realize that he was way over line and had wounded the brunet. "Fine with me! I could probably fuck myself better than you could!"

"I'm sure Kasuka could do it better," he sneered. "Why settle for a brother complex when you can have the real thing?"

Shizuo slammed his fist into his face, sending Izaya back into the wall he had him cornered against. The brick cracked dangerously as did Izaya's skull and the brunet crumbled to the ground. Realizing that he had stepped way over the line and had wounded the brunet, Shizuo's anger faded and he instantly tried to reconcile with his lover. "Flea, I'm sorry. It's just my temper. You know I didn't mean it."

"Leave me alone," Izaya growled, pulling away from the blond and struggling to stand up on his own two feet. He was seeing stars and pairs of everything and he was sure that he now had a lovely black eye to match the equally-lovely baseball bruise to go along with another concussion. "I hate you. We're done."

"No, we're not. Let me make it up to you, please," Shizuo pleaded pitifully but Izaya would not give in.

"Yes, we're done, you stupid monster. I hate to remind you this, but we were never something to begin with," he said miserably.

"Izaya, I didn't mean it. I was angry, you know that," Shizuo said desperately.

"You wouldn't have said it if somewhere deep down in your protozoan brain you didn't mean it," he answered softly, hurt.

"Izaya, I didn't-"

"I don't want to hear it," Izaya interrupted coldly. "You know what the best part is, Shizuo? I can't even dump your sorry ass properly because according to you, we don't even have a relationship! Right? Because I just manipulated your sorry ass into this fucked up version of a relationship! Because that's all I ever do!"

"Stop it," Shizuo said, knowing that Izaya was intentionally being harsh and cruel. He knew that when Izaya got hurt, he would fall back onto the insults, but Shizuo was not going to let it get to him.

"You hate me," Izaya continued, refusing to stop until he had damaged Shizuo in some way. "You've hated me since we've met. Guess what? The feeling's mutual. Oh, and by the way, my head still hurts thanks to you!"

With that said, Izaya spun on his heel and stormed off, disappearing into the crowd, still livid, leaving Shizuo stunned, alone and most of all, heartbroken.

_[Final Notes]  
This experiment was a complete failure and waste of time._


	7. Chapter 7

**Disclaimer: I don't own DRRR!**

**A/N:**  
This was short. I couldn't get it longer for the life of me. And I think I made Shizuo too ooc. OTL

* * *

_[Day 6 of the Development of Psychosexuality]_

Izaya was pissed.

No, he was absolutely livid

Take a furious Shizuo on his worst day, multiply by it by ten and you still wouldn't get anything relatively close to what Izaya was feeling.

It was all Shizuo's fault, really. His current object of affection (well, anger now) was a stupid protozoan brute who had no business sticking his nose into Izaya's personal paperwork. Those words were meant for his eyes only and they were merely observations. It was plain and simple: Shizuo clearly overreacted and Izaya was not at fault, at all.

He then silently cursed at Freud when he realized he was using one of his defense mechanisms. Stupid Freud. Of course he would come back and bite him in the ass.

Izaya buried his face deep into his palms as a heavy sigh of frustration escaped his lips. This was all his fault. He had no right to write these horrible things about Shizuo, especially since the blond was nothing but kind to him. If Shizuo had any reason to doubt their relationship, it was because Izaya had given him all those reasons. This was completely and entirely his fault.

And then he knew what he had to do.

He headed down to the nearest office supplies store and bought a paper shredder. After dragging it home, Izaya proceeded to feed it all fifty-eight pages of Shizuo's personal file. An hour later, he was surrounded by homemade confetti and searching for a cupcake recipe online.

His house's kitchen might have not been like the school's fancy Home Ec room, but it would do just fine. The brunet completely took over the kitchen and swatted his sisters away who attempted to eat up his chocolate icing.

It was late in the afternoon when Izaya was done putting together an 'apology package'. He stared at the package wordlessly, wondering if a simple present could mend all the hurt between them and fix a relationship. He wondered if Shizuo was still mad, or if he moved on already. Sighing, he decided that he would just have to man up and stop hiding.

Izaya set the box down onto the Heiwahima's doormat, and then rang the doorbell. He stepped back quickly, literally diving into the shrubbery to hide. Kasuka answered the door, looked around confusedly when nobody was there and was about to close the door until he saw the white box on the doorstep.

"Brother, it's for you," Kasuka softly murmured as he noticed Shizuo's name was neatly penned onto the ribbon. Shizuo came to the door, expecting a person and frowned when nobody was there. "Present," his younger brother said and headed back into the house.

Shizuo picked up the package from his doorstep and sighed as he recognized the handwriting as Izaya's. Ah, he must truly be a masochist to open whatever revenge-seeking gift Izaya gave him. He undid the bow slowly and lifted the lid to see eight iced cupcakes that spelled out, "_I'M SORRY_" as well as some poorly folded paper cranes and stars as fillers. Shizuo sighed and then called out, "Stupid flea, come out."

Izaya sheepishly showed his face as he crawled out of the shrubbery and awkwardly murmured, "Hi," with a small wave.

"Hi," Shizuo answered back and picked up a crane from the box. "Heh, and you said I was bad at origami."

Izaya awkwardly shuffled his feet, unable to find a proper response to that. "I shredded your file," he blurted out.

"Oh?" the blond answered, though he didn't even seem to care.

"What are you oh'ing about? I just said I scrapped the entire experiment," he elaborated.

Shizuo looked and him blankly and shrugged. "I thought I'd be relieved, but honestly, I don't care," he admitted.

Izaya looked at him with wide eyes. "What do you mean you don't care?"

"Exactly that," he answered, "I guess I just overreacted when I read it at first. Now, I realize that it's just typical of you, no offense."

The brunet still stared at him, wide-eyed and confused. "I don't understand..." he stammered. "Are you still angry at me?"

"Nope," he answered. "I overreacted, that's all, and I'm sorry, too, about what I said about your intentions."

Izaya cringed at the reminder. "No, no, I overreacted too," he answered, deciding that if Shizuo could be the bigger man, then so could he. "I know you didn't mean it. I was just being stupid and insecure and-."

Shizuo looked in the box, frowned and then completely changed the subject by interrupting, "Did you make the paper stars out of my shredded file?"

Izaya looked at him startled. Way to kill the mood. "Well, yes, but-"

"Wanna come in?" Shizuo asked, gesturing to the front door.

"Shizuo, I'm sorry!" Izaya exclaimed, loudly, trying to get his attention before he had to suffer from any more awkwardness.

"I know, I heard you the first time," the blond answered with a warm smile and pointed to the door again.

"This is all wrong," Izaya said, starting to panic. It wasn't playing out the way it was supposed to be, which in Izaya's mind was Shizuo harshly rejecting the present and slamming the door in face. "You're supposed to be mad at me. Why aren't you mad at me? You're doing this wrong."

Shizuo raised an eyebrow in amusement and played along. "And how exactly am I supposed to act, Izaya?"

"You're supposed to yell at me. Loudly. And try to hit me again," he sputtered.

"But that wouldn't be nice. I have neighbors. They've already witnessed me punching you in the face once already," Shizuo said, balancing the box in one hand as reached to tilt Izaya's face towards him, inspecting the black eye he gave him.

"There's something seriously wrong with you," Izaya said as he shyly averted his gaze from Shizuo's soul-searching eyes. "You're unusually calm. You should have steam coming out of your ears."

Shizuo chuckled lightly and shook his head. "I looked up that sublimation thing you told me about. It doesn't pertain to _only_ sex." Izaya looked at him in surprise when he stated this. "Sublimation is the conversion of one's emotions into a productive task," he said smartly. "I took my anger out on something else."

Izaya studied him carefully and then said, "That's complete bullshit. I don't believe one word of that."

Shizuo laughed at how easily Izaya could read him. "I really did and sure, it didn't work out, but I really am not mad at you. Seriously." He opened the front door for Izaya. "I forgive you, so you'll forgive me?"

"Yeah, definitely," Izaya answered as he followed Shizuo inside to the kitchen. Wordlessly, he watched as Shizuo emptied the box of its paper cranes and stars onto the table before placing it into the fridge. Suddenly, he realized something.

"What are you grinning about?" Shizuo asked, noticing the sudden smile spreading onto the brunet's handsome features.

Izaya smirked and approached Shizuo slowly, wrapping his arms his neck when the space closed between them. "So," Izaya murmured in a breathy tone against his ear, "since I scrapped that experiment, how about we pick up right where he left off a week ago?" He brushed his lips against Shizuo's and stilled, waiting for the blond to make the next move.

Shizuo pressed close to Izaya, kissing him deeply as he urgently pressed the smaller man tightly against him. A shiver went down Izaya's spine as the blond's calloused fingers settled down on his waist, his shirt riding up as Shizuo held him tightly. Izaya moaned softly, eyes squeezed shut in elation as he felt Shizuo's familiar touch on him and his thinking process was slowly reduced to incoherent thoughts as Shizuo... oh...

Abruptly, Shizuo's ministrations stilled and he stepped back from the smaller man. He looked at him with something akin to amusement. "You know, we still have one more day in your experiment. One more day waiting couldn't hurt," he said with wink.

Izaya deadpanned. "You have got to be kidding me."

"We need to turn our urges into something more productive," Shizuo said with a cheeky grin.

"Well, whoever said that was an idiot," Izaya growled.

"Nice try," the blond smiled. "But you've already made me suffer for almost a week now. Don't you think I should get a little fun, too?"

_[Final Notes]  
What a tease._


	8. Chapter 8

**Disclaimer: I don't own DRRR!**

**A/N:** Last part. Thanks for reading~!

* * *

_[Day 7 of the Development of Psychosexuality AKA The Last Day]_

Izaya is excited and his joy does not go unperceived by his beloved Shizu-chan, though it's not like Shizuo can ignore such elated mirth. Izaya's being touchy again and it seems he can't go for five minutes without tangling his fingertips to his or brushing his body against _any_ part of Shizuo (And this isn't an exaggeration for Shinra-san actually timed it). But it's not like all of Izaya's effusive affections are unrequited for Shizuo is just as happy. It's the last day of the brunet's psychology experiment and everything is going to go back to the way it was, if not better.

"Shizu-chan? Want to sleep over at my place tonight?" Izaya asks him that morning before class. Shizuo blushes that charming shade of pink Izaya adores and nods shyly. It's still so endearing to the future-informant that despite all the kinky things they've done, the brute still manages to act like a blushing virgin. Izaya chuckles at this, while wondering why he's not the one topping. "You should come home with me after school then," he said with a nod. "Or is there another club you're going to try out? You know, you never actually told me what you sublimated your angry emotions into!"

"That's a secret," Shizuo replies, glad that he can change the subject now. He may adore Izaya to no end, but that doesn't mean he'll flaunt his sex life publicly.

"I'll find out eventually!" Izaya responds with a catty grin. "After all, I will become the greatest information broker of all time!" He catches Shizuo by the belt loops, stands on his toes and gives him a deep kiss. When he pulls away, his eyes are half-lidded and he has a goofy grin plastered on his face.

"Get a room, would you?" Shinra interrupts, intentionally ruining the moment.

"No! Don't get a room! You're fine where you are!" Erika desperately squeals, trying to get her daily dose of hot yaoi action.

Kadota and Yumasaki facepalm and make their way to class, not wanting any part in this.

For Izaya, class is torture. He's usually not so riled up but he can't help but to feel giddy. Maybe it's just because his relationship with Shizuo is better than ever. Either way, he doesn't pay attention in class and spends his day looking out the window, much to the displeasure of all his teachers.

After school, Shizuo insists he goes to cooking club with the girls. His head's in the clouds and he messes up his recipe, swapping baking soda for baking powder. It turns out Shizuo went with Shinra to science club after school and did something so unspeakable and horrifying that there was a unanimous vote to impeach Shinra as president of the science club. Izaya regrets missing out on this and whenever he asks about it, Shizuo will guiltily cringe and apologize, former-President Shinra will brood in his 'Corner of Woe', and the other science club members will tremble in fear. Izaya vows to find out one day, but at the same time, he can't help but wonder just how damaged he would have ended up if he had visited.

They walk to Izaya's apartment afterwards, pinkies hooked together modestly, as Izaya reassures Shizuo that Shinra isn't mad about his impeachment. Shizuo vows to _never_ join an afterschool club again and Izaya does his best to show his unwavering support.

"So I was thinking," Izaya starts suggestively.

"God help us all," Shizuo interrupts only to tease.

"I have good ideas," the brunet retorts, pretending to be offended. "I did come up with this experiment, didn't I?" and Shizuo can't help but to snort. Izaya ignores this and continues on. "How about you take me on the first hard surface you see when we get home?"

Shizuo frowns and looks at the clock on his cell phone. "But the day's not over yet. We'd be breaking the rules to the experiment."

Izaya looks at the blond in disbelief, wondering if he heard him wrong. "What...?"

"The experiment is to go a whole week. Today's not over yet."

Nope, he regretfully heard him right. "Considering _I_ designed the experiment and _I_ made the rules, I'll allow this breach in conduct," Izaya growls, determined to get what he wants.

"Nice try, but any scientist knows you should always follow procedure to avoid accidents," the blond tells him smugly and Izaya thinks he's learned this in science club. If so, then Shinra deserved to get impeached.

Izaya pouts in response, hoping to use his charms to seduce the blond. Shizuo is impervious to this of course and shrugs. "You were the one who designed the experiment," he pointed out and continued walking. His pinky slips from Izaya's and he stops, looking over his shoulder in confusion, wondering why the brunet isn't walking with him anymore.

"You're such a tease," Izaya jabs as he picks up his pace to catch up with Shizuo. "Biggest tease ever."

Shizuo grins at this, taking it as a compliment and they make their way back to Izaya's apartment in silence. Much to Izaya's dismay, Shizuo does _not_ take him on the first hard surface he sees and settles down to do some homework. Yes, fucking homework. Izaya hates him with a burning rage right now just because the stupid blond is seductively biting at the end of his pencil as he frowns and tries to figure out how to solve an arithmetic problem. Shizuo is being so oblivious and concentrated on his homework that he doesn't even _realize_ the effect he has on Izaya.

The dumb blond looks up when he realizes that Izaya is staring at him. Eyes locked, he slowly pulls the pencil from his mouth and hesitantly asks, "What?"

Izaya shakes his head in disbelief and storms off, deciding to start early on dinner to keep his mind off Shizuo. Izaya decides this isn't right, since it's Shizuo whose supposed to be nearly losing it and ready to jump him. So, two can play at that game.

The brunet digs up his Hello Kitty apron, remembering that Shizuo has a thing for aprons, and figures maybe he can seduce him into ending the experiment early. Lucky for him, Shizuo comes wandering into the kitchen and looks at Izaya with wide eyes. Kitchen counter sex, Izaya decides, is hot and he smiles seductively in his direction. Shizuo moves towards him, nearly pinning him against the kitchen island with his body and leans in, breath hot against his ear.

"Cute apron," Shizuo murmurs, reaches past him and picks up an apple from the kitchen island. With that said, he turns and leaves to return to doing homework (instead of him) and leaves Izaya fuming at his failed attempt at seduction.

And thus, Izaya sublimates his anger into cooking curry katsu and then blazes through arithmetic problems in rage. Shizuo blinks at the scorch marks left by the pencil and wonders if Izaya's taken another baseball to the head. More like baseball _bat_, he silently adds, when the brunet gets on the computer and begins ranting online to his chat buddies. Shizuo feels bad for Setton-san and Tanaka Taro-san and actually considers ending the experiment early for Izaya's health.

Shizuo tries to start a conversation during dinner, telling him about Kasuka taking a drama class at the middle school. He happily talks about Kasuka taking the lead role in a production all the while accidentally getting curry sauce on his fingers. Instead of wiping them on a napkin, Shizuo chooses to lick it off his fingers, complimenting Izaya's cooking as he does so.

Though, all of it falls on deaf ears as Izaya's too focused on Shizuo looking hot while licking his fingers and he thinks of other things that he can lick. "I hate you," Izaya finally says and throws a napkin in his direction. As he storms out of the room, Shizuo grins and wipes his fingers on the napkin. He really is such a tease.

At night, when they're in bed, Shizuo kisses Izaya long and passionately before turning away to turn off the lights. "Good night," he said and prepared to go to sleep.

"What the fuck?" Izaya snaps, pouncing on Shizuo, throwing a leg over his hips to straddle him. "You're doing this on purpose," he says accusingly.

Shizuo feigns innocence and answers, "I don't know what you're talking about," though he knows exactly what Izaya's talking about, considering his lower regions are reacting to the informant straddling him.

"You're the worst," Izaya remarks, sliding off much to Shizuo's disappointment and settling next to him. He's got a much better plan now and leaves the blond alone for the rest of the day.

At exactly 12:01AM, Izaya rouses the brute from his sleep by promptly shoving his tongue down his throat. It's actually a pleasant way to be woken up, being frantically kissed by a lover and all.

"What are you doing?" Shizuo sleepily asks in between kisses.

"It's a new day," Izaya answers, moving to his jaw line. "It's after midnight. It's the next day. You're going to fuck me now."

"Bossy," Shizuo retorts but obliges nonetheless, practically manhandling him as he tilted their center of gravity so that Izaya is pinned beneath him. The blond takes his sweet time to unbutton Izaya's night shirt and is sure to lavish every bit of exposed skin with a breathy kiss. Izaya reacts sensitively to Shizuo touch, sincerely missing its weeklong absence. He's really missed this and he knows Shizuo has, too. Izaya's feeling hot and each part Shizuo touches feels like it's catching on fire. He groans when Shizuo settles himself between his legs and slicks his fingers before gently pressing it into his entrance.

The brunet moans, digging fingers into Shizuo's damp hair and urges him to hurry. His cock is twitching in response to Shizuo's ministrations and by the time the blond presses in a second finger, Izaya's already begging for release. He lets out a ragged moan and writhes as Shizuo presses a third finger into his tight entrance. He pumps them in and out slowly and then boldly leans in to suck Izaya off as he does so. Izaya gasps as Shizuo's skillfully runs his tongue along the length of his shaft. Fingers still in him, Izaya bucks his hips, urging the blond to take more of him. Shizuo obliges, practically deep-throating him and as Izaya comes, he swears loudly in- _Russian..?_

Shizuo removes his fingers from Izaya's now stretched entrance and positions himself. The brunet moans as his aching muscles protest to being stretched again by something _much_ larger and more satisfying. Izaya arches his back and presses close to Shizuo, nearly squealing in delight as he does so. Shizuo takes this as a sign to start thrusting rhythmically into the smaller student, seemingly penetrating him deeper with each thrust. He hits his sweet spot each time and Izaya is seeing stars. His voice is hoarse from his loud moans and all he can do is clumsily wrap his legs around Shizuo's waist and try and stay conscious.

Izaya finally comes undone when Shizuo reaches down between them to grasp the brunet's stiff member. "Shizuo!" Izaya cries out as he reaches a state of pure bliss. Shizuo grunts his name in response as he continues pounding the informant into the mattress until he finds his own release shortly afterwards, releasing his hot seed into Izaya's channel as he does so.

Shizuo catches himself on his arms, stopping himself from collapsing onto the informant. Izaya takes this moment to pepper Shizuo's neck with kisses and love bites as they slowly come down from their intense sexual highs.

"I love you," Izaya confesses as Shizuo settles into bed and pulls the brunet against him.

"I love you, too," Shizuo answers immediately, sincerely, as he rubs his nose affectionately against Izaya's feathery hair. And as they drift to sleep, Izaya knows that they'll have a hard time waking up in the morning.

_[Final Notes]  
Totally worth it_


End file.
